The chemical and petroleum process industries use many types of vessels in processing and/or purifying chemicals. The processing and/or purifying often involves mixing fluids and passing a mixture of the fluids over an adsorption bed, a reactor bed, or passing the fluids over trays in a distillation column. One particular type of vessel is a multibed reactor, with cocurrent flow of a process fluid and a feed fluid. The multibed reactor comprising a series of solid particulate beds of catalyst particles that react a process fluid flowing over the beds. The efficiency and life of the catalyst bed are influenced by the distribution of fluid flowing over the bed. The feed fluid can be added as a reactant, or as a quench fluid, for a process stream that flows over a catalyst bed. Redistribution and mixing is important for maximizing catalyst bed life, and maximum utilization of the catalyst by preventing dead zones, or zones in the catalyst bed having low flow.
Other types of vessels include countercurrent flow reactors, separation vessels having cocurrent flow, or countercurrent flow. Many of these processes are affected by the manner in which a fluid, to be reacted, separated, or otherwise processed, is distributed in the vessel.
One important type of process is the adsorption separation process. The adsorption separation process has been developed through simulated moving bed (SMB) technology, where the adsorption separation process can be operated on a continuous basis. The simulation of a moving adsorbent bed is described in U.S. Pat. No. 2,985,589 (Broughton et al.). In accomplishing this simulation, it is necessary to connect a feed stream to a series of beds in sequence, first to bed no. 1, then to bed no. 2, and so forth for numerous beds, the number of beds often being between 12 and 24. These beds may be considered to be portions of a single large bed whose movement is simulated. Each time the feed stream destination is changed, it is also necessary to change the destinations (or origins) of at least three other streams, which may be streams entering the beds, such as the feed stream, or leaving the beds. The moving bed simulation may be simply described as dividing the bed into series of fixed beds and moving the points of introducing and withdrawing liquid streams past the series of fixed beds instead of moving the beds past the introduction and withdrawal points.
There are many different process requirements in moving bed simulation processes, resulting in different flow schemes. For example, in addition to the four basic streams described in Broughton (U.S. Pat. No. 2,985,589), it may be desirable to utilize one or more streams to purge, or flush, a pipeline or pipelines. A flush stream is used to prevent undesirable mixing of components. The flush substance is chosen to be one which is not undesirable for mixing with either main stream, that being purged or that which enters the pipeline after flushing is completed. U.S. Pat. No. 3,201,491 (Stine et al.) may be consulted for information on flushing lines as applied to the process of Broughton (U.S. Pat. No. 2,985,589). In addition, the efficiency of the process has many factors, including the redistribution of fluid from one bed to the next, and the mixing and redistribution of a process fluid with one of the feed streams between two beds.
Improvements in the fluid distributers can improve efficiency and increase the life of the adsorbents in the adsorption separation system.